Did Facebook manipulate your mood for a study?

Data scientists altered news feeds back in 2012 so that unknowing users received either happier or sadder news than average on their timelines to test how it would affect them.

The result? Those who had the week of positive news posted more upbeat comments, while those who received the negative stories and posts would share sadder messages.

The study was released in the "Proceedings of the National Academy of Sciences," and has been drawing criticism from some users who find it an invasion of privacy. Facebook is legally allowed to conduct the study under it's user terms and agreements, which says they can use your profiles for data analysis, testing and research.